U.S. patent application number 17/643019 was filed with the patent office on 2022-09-15 for tool body of cutting tool for indexable inserts, and round milling insert.
This patent application is currently assigned to TUNGALOY CORPORATION. The applicant listed for this patent is TUNGALOY CORPORATION. Invention is credited to Ryuichi SAJI, Hiroya SHIKAMA.
Application Number | 20220288706 17/643019 |
Document ID | / |
Family ID | 1000006064516 |
Filed Date | 2022-09-15 |
United States Patent
Application |
20220288706 |
Kind Code |
A1 |
SHIKAMA; Hiroya ; et
al. |
September 15, 2022 |
TOOL BODY OF CUTTING TOOL FOR INDEXABLE INSERTS, AND ROUND MILLING
INSERT
Abstract
Provided are a tool body of a cutting tool for indexable inserts
and a round milling insert that are configured not to cause
floating or rattling when the round milling insert is mounted, by
keeping the contact part between the round milling insert and the
tool body at a predetermined part. The tool body includes a
recessed portion provided so that only one of a plurality of
protrusions is fitted thereto, the plurality of protrusions being
formed in the round milling insert so as to protrude in the radial
direction, wherein the recessed portion has both inner surfaces
thereof formed of curved surfaces in such a manner that the
distance therebetween gradually decreases toward a depth portion,
at the contact area between the recessed portion and said
protrusion fitted thereto out of the plurality of protrusions. The
round milling insert mounted onto such tool body includes a
plurality of protrusions formed so as to protrude in the radial
direction, any of the plurality of protrusions being able to be
fitted into a recessed portion provided on a mounting seat of the
tool body, wherein each of the protrusions has both outer surfaces
thereof formed of curved surfaces in such a manner that the
distance therebetween gradually decreases toward a tip of the
protrusion, at the contact area between the protrusion and the
recessed portion into which the protrusion is fitted.
Inventors: |
SHIKAMA; Hiroya; (Iwaki-shi,
JP) ; SAJI; Ryuichi; (Iwaki-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
TUNGALOY CORPORATION |
Fukushima |
|
JP |
|
|
Assignee: |
TUNGALOY CORPORATION
Fukushima
JP
|
Family ID: |
1000006064516 |
Appl. No.: |
17/643019 |
Filed: |
December 7, 2021 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B23C 5/2213 20130101;
B23C 5/006 20130101; B23C 2200/045 20130101 |
International
Class: |
B23C 5/22 20060101
B23C005/22; B23C 5/00 20060101 B23C005/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 10, 2021 |
JP |
2021-038029 |
Claims
1. A tool body onto which a round milling insert is mounted to
configure a cutting tool for indexable inserts, wherein a mounting
seat for mounting the round milling insert includes a seating
surface coming into contact with one surface of the round milling
insert, a female screw hole provided in the seating surface to
receive a male screw for fixing the round milling insert, and a
recessed portion provided so that only one of a plurality of
protrusions is fitted thereto, the plurality of protrusions being
formed in the round milling insert so as to protrude in a radial
direction, and the recessed portion has both inner surfaces thereof
formed of curved surfaces in such a manner that a distance
therebetween gradually decreases toward a depth portion, at a
contact area between the recessed portion and said protrusion
fitted thereto out of the plurality of protrusions.
2. The tool body according to claim 1, wherein in the contact area,
the inner surfaces respectively include ridge lines facing each
other and protruding toward an internal space.
3. A round milling insert mounted onto a tool body to configure a
cutting tool for indexable inserts, the round milling insert
comprising a plurality of protrusions formed so as to protrude in a
radial direction, any of the plurality of protrusions being able to
be fitted into a recessed portion provided on a mounting seat of
the tool body, wherein each of the protrusions has both outer
surfaces thereof formed of curved surfaces in such a manner that a
distance therebetween gradually decreases toward a tip of the
protrusion, at a contact area between the protrusion and the
recessed portion into which the protrusion is fitted.
4. The round milling insert according to claim 3, wherein the outer
surfaces of the protrusion are formed in such a manner that an area
of a cross section parallel to a bottom surface of the protrusion
gradually increases in a direction away from the bottom surface,
the bottom surface being in contact with a seating surface of the
mounting seat.
5. The round milling insert according to claim 4, wherein the outer
surfaces are each formed as a part of a circular truncated cone
surface.
Description
BACKGROUND
Field
[0001] The present invention relates to a tool body of a cutting
tool for indexable inserts in which a round milling insert is used
as a indexable insert, and the round milling insert.
Description of Related Art
[0002] In a conventional cutting tool for indexable inserts in
which a round milling insert is used as a indexable insert, in
order to stably fix the round milling insert to a support seat,
said cutting tool is designed in such a manner that the side faces
of a protrusion of the round milling insert come into contact with
the side faces of a recessed portion of the support seat (see
Patent Publication JP-A-2014-24124).
SUMMARY
[0003] Although the side faces of the protrusion of the round
milling insert are designed to come into contact with the side
faces of the recessed portion of the support seat of the tool body,
it is often the case that these side faces actually do not come
into surface contact with each other due to machining accuracy or
assembly error but come into point contact or line contact with
each other at some parts. The side faces that come into contact
with each other at unexpected parts may cause the round milling
insert to float or rattle.
[0004] The present invention was contrived in order to solve these
problems, and an object thereof is to provide a tool body of a
cutting tool having a indexable insert and a round milling insert
that are configured not to float or rattle when mounted, by keeping
the contact part between the round milling insert and the tool body
at a predetermined scheduled part.
[0005] A tool body according to one aspect of the present invention
is a tool body onto which a round milling insert is mounted to
configure a cutting tool for indexable inserts, wherein a mounting
seat for mounting the round milling insert includes a seating
surface coming into contact with one surface of the round milling
insert, a female screw hole provided in the seating surface to
receive a male screw for fixing the round milling insert, and a
recessed portion provided so that only one of a plurality of
protrusions is fitted thereto, the plurality of protrusions being
formed in the round milling insert so as to protrude in a radial
direction, and the recessed portion has both inner surfaces thereof
formed of curved surfaces in such a manner that a distance
therebetween gradually decreases toward a depth portion, at a
contact area between the recessed portion and said protrusion
fitted thereto out of the plurality of protrusions.
[0006] A round milling insert according to one aspect of the
present invention is a round milling insert mounted onto a tool
body to configure a cutting tool for indexable inserts, the round
milling insert comprising a plurality of protrusions formed so as
to protrude in a radial direction, any of the plurality of
protrusions being able to be fitted into a recessed portion
provided on a mounting seat of the tool body, wherein each of the
protrusions has both outer surfaces thereof formed of curved
surfaces in such a manner that a distance therebetween gradually
decreases toward a tip of the protrusion, at a contact area between
the protrusion and the recessed portion into which the protrusion
is fitted.
[0007] The present invention can provide a tool body of a cutting
tool for indexable inserts and a round milling insert that are
configured not to cause floating or rattling when the round milling
insert is mounted, by keeping the contact part between the round
milling insert and the tool body at a predetermined part.
BRIEF DESCRIPTION OF DRAWINGS
[0008] FIG. 1 is an overall perspective view of a cutting tool
according to an embodiment;
[0009] FIGS. 2A and 2B are overall perspective views of a round
milling insert with six corners;
[0010] FIGS. 3A and 3B are overall perspective views of a round
milling insert with eight corners;
[0011] FIG. 4 is a partially enlarged view of a mounting seat;
[0012] FIG. 5 is a diagram of the cutting tool viewed from the
side;
[0013] FIG. 6 is a cross-sectional view showing a contact section
between a round milling insert and a tool body; and
[0014] FIG. 7 is a diagram schematically showing a contact area
between the round milling insert and the tool body.
DETAILED DESCRIPTION
[0015] An embodiment of the present invention is now described
hereinafter with reference to the accompanying drawings. Note that,
in each diagram, those having the same reference numerals have the
same or similar configurations. In addition, in each diagram, when
a plurality of structures with the same or similar configuration
are present, reference numerals may be given to some of the
structures and the same reference numerals may not be given to the
other structures, in order to avoid complications.
[0016] FIG. 1 is an overall perspective view of a cutting tool 100
which is a cutting tool for indexable inserts according to the
present embodiment. The cutting tool 100 is composed of a tool body
200, a round milling insert 300 to be mounted on the tool body, and
a male screw 500 which is a clamp screw for fixing the round
milling insert 300 to the tool body.
[0017] Mounting seats 210 are provided on an outer peripheral
portion of a tip of the tool body 200 at regular intervals along a
circumferential direction. As illustrated in the diagram, the tool
body 200 according to the present embodiment is provided with five
mounting seats at intervals of 72 degrees. The round milling insert
300 is fixed to each of the mounting seats 210 by means of the male
screw 500.
[0018] FIGS. 2A and 2B are overall perspective views of the round
milling insert 300 with six corners that has six mounting parts.
FIG. 2A is a bird's-eye view of the round milling insert 300, and
FIG. 2B is a diagram looking up at the round milling insert 300.
The round milling insert 300 has a substantially circular truncated
cone shape as a whole, and includes a large-diameter upper surface
311, a small-diameter bottom surface 313, and a side surface 312
connecting the upper surface 311 and the bottom surface 313. A
cutting blade 320 is provided along a circumferential ridge line of
the upper surface 311. When the round milling insert 300 is mounted
on a mounting seat 210 of the tool body 200, the cutting blade 320
partially protrudes from the tip of the tool body 200.
[0019] The round milling insert 300 includes a mounting hole 330
through which the male screw 500 penetrates so as to penetrate the
central axis of the circular truncated cone shape. Drilling
portions 353 are provided at equal intervals in the circumferential
direction on the bottom surface 313 side of substantially the lower
half of the circular truncated cone shape. Since the round milling
insert 300 is an insert with six corners, six drilling portions 353
are provided at intervals of 60 degrees. The drilling portions 353
each have a shape obtained by scraping and removing a part
extending from the side surface 312 to the bottom surface 313. As a
result of providing the drilling portions 353, a protrusion 350 is
formed between two drilling portions 353 adjacent to each other, so
as to protrude in a radial direction. The round milling insert 300
has six protrusions 350. In the present embodiment, viewing from
the bottom surface 313 side, the outer surface of each of the
protrusions 350 in the counterclockwise direction is a first outer
surface 351, and the outer surface of the same in the clockwise
direction is a second outer surface 352.
[0020] The six protrusions 350 have an identical shape.
Specifically, as will be described hereinafter, any of the
protrusions 350 can be fitted into a recessed portion provided in
the mounting seat 210 of the tool body 200. In other words, the
round milling insert 300 having the six protrusions 350 can be
fixed to the mounting seat 210 in six directions (phases) by
fitting the protrusion 350 into the recessed portion provided in
the mounting seat 210. When the cutting blade 320 reaches its usage
limit in a certain phase, the user can change the phase and
reattach the round milling insert 300 to use the cutting blade 320
again.
[0021] FIGS. 3A and 3B are overall perspective views of a round
milling insert 400 with eight corners that has eight mounting
parts. FIG. 3A is a bird's-eye view of the round milling insert
400, and FIG. 3B is a diagram looking up at the round milling
insert 400. The structure of the round milling insert 400 is the
same as that of the round milling insert 300 with the six corners.
The round milling insert 400 has a substantially circular truncated
cone shape having the same size as the round milling insert 300 as
a whole, and includes a large-diameter upper surface 411, a
small-diameter bottom surface 413, and a side surface 412
connecting the upper surface 411 and the bottom surface 413.
[0022] As with the round milling insert 300, a cutting blade 420 is
provided along a circumferential ridge line of the upper surface
411, and includes a mounting hole 430 through which the male screw
500 penetrates so as to penetrate the central axis of the circular
truncated cone shape. As with the round milling insert 300, the
round milling insert 400 includes drilling portions 453 arranged at
equal intervals in the circumferential direction on the bottom
surface 413 side of substantially the lower half of the circular
truncated cone shape, but since the round milling insert 400 is an
insert with eight corners, eight drilling portions 453 are provided
at intervals of 45 degrees, and as a result, eight protrusions 450
are formed so as to protrude in the radial direction. In the
present embodiment, viewing from the bottom surface 413 side, the
outer surface of each of the protrusions 450 in the
counterclockwise direction is a first outer surface 451, and the
outer surface of the same in the clockwise direction is a second
outer surface 452.
[0023] The eight protrusions 450 have an identical shape and also
have the same shape as that of the protrusions 350 of the round
milling insert 300. Therefore, any of the protrusions 350 can be
fitted into the recessed portion provided in the mounting seat 210
of the tool body 200. In other words, the round milling insert 400
having the eight protrusions 450 can be fixed to the mounting seat
210 in eight directions (phases) by fitting the protrusion 450 into
the recessed portion provided in the mounting seat 210. When the
cutting blade 420 reaches its usage limit in a certain phase, the
user can change the phase and reattach the round milling insert 400
to use the cutting blade 320 again.
[0024] Note that although the present embodiment has described the
round milling insert 300 with the six corners and the round milling
insert 400 with the eight corners, any round milling insert having
any number of corners can be mounted onto the tool body 200 as long
as said round milling insert has protrusions in the same shape as
the round milling inserts 300 and 400. In the following
description, an example of mounting the round milling insert 300 is
described, but the example can also be applied to mounting other
round milling inserts.
[0025] FIG. 4 is a partially enlarged view of the mounting seat 210
in which the round milling insert 300 is removed in part A shown in
FIG. 1. The mounting seat 210 includes a seating surface 212 coming
into contact with the bottom surface 313 of the round milling
insert 300, a female screw hole 213 provided in the seating surface
212 to receive the male screw 500, and a recessed portion 220
provided so that one of the protrusions 350 of the round milling
insert 300 is fitted thereto.
[0026] The recessed portion 220 is drilled in a direction away from
the central axis of the female screw hole 213 (depth direction),
and as a result, a first inner surface 221 and a second inner
surface 222 are formed as two inner surfaces with respect to the
depth direction. In the present embodiment, in a bird's-eye view of
the seating surface 212, the inner surface of the recessed portion
220 in the clockwise direction is the first inner surface 221, and
the inner surface of the same in the clockwise direction is the
second inner surface 222.
[0027] FIG. 5 is a diagram of the cutting tool 100 viewed from the
side. FIG. 6 is a cross-sectional view taken along B-B shown in
FIG. 5, that is, a cross-sectional view taken along a plane
including the protrusion 350 of the round milling insert 300
mounted on the mounting seat 210. More specifically, FIG. 6 is a
cross-sectional view showing a contact section between the round
milling insert 300 and the tool body 200.
[0028] As described above, the protrusion 350 of the round milling
insert 300 is fitted into and fixed to the recessed portion 220 of
the mounting seat 210. The phase of the round milling insert 300 is
fixed by the meshing between the protrusion 350 and the recessed
portion 220. In other words, the meshing between the protrusion 350
and the recessed portion 220 functions to stop the round milling
insert 300 from turning.
[0029] The areas in the recessed portion 220 that are scheduled to
come into contact with the protrusion 350 are the first inner
surface 221 and the second inner surface 222, which are part of the
both inner surfaces of the recessed portion 220. The areas in the
protrusion 350 that are scheduled to come into contact with the
recessed portion 220 are the first outer surface 351 and the second
outer surface 352, which are part of the both outer surfaces of the
protrusion 350. In other words, the first inner surface 221 and the
first outer surface 351 are scheduled to come into contact with
each other, and the second inner surface 222 and the second outer
surface 352 are scheduled to come into contact with each other.
[0030] Once the round milling insert 300 is actually fixed by means
of the male screw 500, either one of the aforementioned surface
pairs may come into contact with each other and a gap may be formed
in the other surface pair, depending on the tolerance and machining
accuracy. In the illustrated example, a gap is formed between the
first inner surface 221 and the first outer surface 351, whereas
the second inner surface 222 and the second outer surface 352 are
in contact with each other. For example, when the round milling
insert 300 is fixed to the mounting seat 210, the first inner
surface 221 and the first outer surface 351 come into contact with
each other as a result of the rotational force of the male screw
500 fastened clockwise, and the second inner surface 222 and the
second outer surface 352 come into contact with each other as a
result of the cutting force generated during cutting
[0031] FIG. 7 is a diagram schematically showing the contact areas
between the round milling insert 300 and the tool body 200.
Specifically, FIG. 7 is a diagram schematically showing a state in
which the round milling insert 300 is slid on the seating surface
212 to slightly separate the protrusion 350 from the recessed
portion 220, the state being observed through the inside of the
protrusion 350.
[0032] As described above, the areas in the recessed portion 220
that are scheduled to come into contact with the protrusion 350 are
the first inner surface 221 and the second inner surface 222, which
are part of the both inner surfaces of the recessed portion 220.
The first inner surface 221 and the second inner surface 222 are
each formed of a curved surface in such a manner that a distance D2
therebetween gradually decreases toward the depth indicated by the
white arrow. Also, the first inner surface 221 and the second inner
surface 222 are developed so as to protrude upward from respective
rising portions thereof at the respective boundaries with the
seating surface 212 toward the internal space, forming a first
ridge line 221a and a second ridge line 222a at the respective
boundaries with upper surfaces of the first and second inner
surfaces. In other words, the first ridge line 221a and the second
ridge line 222a are the portions of the first inner surface 221 and
the second inner surface 222 that protrude the most toward the
internal space of the recessed portion 220. The recessed portion
220 comes into contact with the protrusion 350 by at least either
the first ridge line 221a or the second ridge line 222a.
[0033] As described above, the areas in the protrusion 350 that are
scheduled to come into contact with the recessed portion 220 are
the first outer surface 351 and the second outer surface 352, which
are part of the both outer surfaces of the protrusion 350. The
first outer surface 351 and the second outer surface 352 are each
formed of a curved surface in such a manner that a distance D3
therebetween gradually decreases toward the tip of the protrusion
shape. Furthermore, the first outer surface 351 and the second
outer surface 352 are formed in such a manner that an area S of the
cross section parallel to the bottom surface 313 of the protruding
portion gradually increases in the direction away from the bottom
surface 313. In particular, in the present embodiment, the first
outer surface 351 and the second outer surface 352 are each formed
as a part of a circular truncated cone surface. The protrusion 350
comes into contact with the recessed portion 220 by at least either
the first outer surface 351 or the second outer surface 352.
[0034] By realizing such three-dimensional configuration, the
contact part between the round milling insert 300 and the tool body
200 can be kept at a certain scheduled part, thereby providing the
cutting tool 100 that is configured not to cause floating or
rattling when mounted with the round milling inserts. In addition,
since the ridge lines come into contact with the curved surfaces,
the stress concentration can be relaxed as compared with the
contact with flat surfaces, and the plastic deformation of the
contact portions can be reduced. Furthermore, by limiting the
contact part to at least either the first ridge line 221a or the
second ridge line 222a away from the seating surface 212, the force
for pressing the round milling insert 300 against the seating
surface 212 acts to further suppress the rattling. In the
replaceable round milling insert 400 as well, since the protrusions
450 are formed in the same manner as the protrusions 350, the same
effects can be achieved.
* * * * *